The present invention relates to a gypsum board comprising linings made of coated non-woven fiberglass mats, to processes for producing same and to the coated non-woven fiberglass mats in roll form, used as intermediates in the production of gypsum board of the invention.
Gypsum boards comprising linings of non-woven fiberglass fabrics (non-woven mat) are non-combustible and, hence, may also be used in interior work where it is convenient or required to employ non-combustible building materials. Gypsum boards lined with fiberglass mats have already proven their usefulness. However, a disadvantage inherent in these boards is that upon working with these boards an abrasion of glass fibers may occur which may be rather inconvenient, especially when working overhead. This abrasion may be avoided if the outer surface of the non-woven fiberglass mat has been coated with paper, which may be conventionally adhered by using a synthetic resin binder. Such gypsum boards may be produced in a conventional band line used for gypsum wallboard manufacture. However, because of their paper coating, these building boards have been classified (e.g., in Germany) neither as building material of class A1-DIN 4102 (non-combustible) nor as non-combustible according to ISO-IS 1182-1979. Upon testing in the furnace at 750.degree. C., ignition occurs. Such boards further have a relatively low air and/or steam permeability.
German Patent Application DE 35 08933-A discloses non-combustible gypsum boards comprising a glass fiber layer, wherein a finely divided inorganic material has been uniformly distributed on the outer surface of the glass fiber layer, which material changes with energy consumption under the action of heat. As specific inorganic materials there have been mentioned gypsum (calcium sulfate dihydrate), limestone, dolomite or magnesite, and substances expanding under the action of heat such as vermiculite and perlite. One drawback inherent in these non-combustible boards is that this additional coating with the finely divided inorganic material can be effected only with the use of an organic synthetic resin binder, such as a synthetic resin dispersion. The synthetic resin binders first must be applied onto the non-woven fiberglass mats, followed by coating with the inorganic material and adhesion-bonding. Only upon complete setting of the binder can the fiberglass mat be wound up and conveyed to the band line for making gypsum building boards.